Windows is a versatile and flexible operating system, running on a variety of machine architectures and available in multiple SKUs. It currently supports x86, x64, and ARM architectures. It even used to support Itanium, PowerPC, Alpha, and MIPS (wiki entry). Windows also runs in a multitude of environments; from data centers, laptops, and phones to embedded devices such as ATM machines.
Even with all of this support, the core of Windows remains virtually unchanged on all these architectures and SKUs. Windows dynamically scales up, depending on the architecture and the processor that it’s run on to exploit the full power of the hardware. This same applies to Microsoft Azure as well. So, if you have ever wondered how Windows runs Azure nodes in the data center, read ahead!
As Satya says, “we are building Azure as the worlds computer” and powering the worlds computer shows the ability of Windows to scale up and scale out. To demonstrate this scale, here is a snapshot of taskmgr running directly on the Azure host in a M-series machine (one of the largest VMs available in Azure, showing 896 logical processors) in the data center.